Does chronic exposure to ammonium during the pre-metamorphic stages promote hindlimb abnormality in anuran metamorphs? A comparison between natural-habitat and agrosystem frogs

Abstract

Despite their detrimental effects on locomotion, prevalence of hindlimb abnormalities is increasing in anuran populations worldwide. Among others, agrochemical pollution during the larval stage is a potential cause. However, populations exposed to such a strong selective pressure could evolve resistance. In this work, we examine the potential effects of chronic exposure to ammonium during the pre-metamorphic stages of Pelophylax perezi frogs on metamorph hindlimb abnormality prevalence, as compared with unpolluted-water-reared conspecifics. We conducted the experiment on tadpoles either from natural-habitat or from agrosystem parents. We detected no effect of chronic exposure to ammonium on hindlimb abnormality prevalence in frogs from either habitat, which suggests that the lack of effect detected is not related to resistance evolved in agrosystem frogs.